Is Meat Unhealthy?
Is Meat Unhealthy? Part III
When we consider the health impacts of eating meat, cardiovascular disease is the first thing that comes to mind. Popular diet advocates often hold diametrically opposed views on the role of meat in cardiovascular disease. Even among researchers and public health officials, opinions vary. In this post, I'll do my best to sort through the literature and determine what the weight of the evidence suggests.
Ancel Keys and the Seven Countries Study
Ancel Keys was one of the first researchers to contribute substantially to the study of the link between diet and cardiovascular disease. Sadly, there is a lot of low-quality information circulating about Ancel Keys and his research (1). The truth is that Keys was a pioneering researcher who conducted some of the most impressive nutritional science of his time. The military "K ration" was designed by Keys, much of what we know about the physiology of starvation comes from his detailed studies during World War II, and he was the original Mediterranean Diet researcher. Science marches on, and not all discoveries are buttressed by additional research, but Keys' work was among the best of his day and must be taken seriously.
One of Keys' earliest contributions to the study of diet and cardiovascular disease appeared in an obscure 1953 paper titled "Atherosclerosis: A Problem in Newer Public Health" (2). This paper is worth reading if you get a chance (freely available online if you poke around a bit). He presents a number of different arguments and supporting data, most of which are widely accepted today, but one graph in particular has remained controversial. This graph shows the association between total fat intake and heart disease mortality in six countries. Keys collected the data from publicly available databases on global health and diet:
Read more »
This post was written by Stephan Guyenet for Whole Health Source.
Is Meat Unhealthy? Part II
Thursday, March 26, 2015 2:19 PM
Over time, animals adapt to the foods they regularly consume. This is how archaeologists can, for example, determine that Triceratops was an herbivore and Tyrannosaurus was a carnivore just by looking at the structure of the skeleton. Adaptations to diet extend beyond skeletal structure, into digestion, metabolism, the brain, musculature, and other aspects of physical function. What is our evolutionary history with meat?
Human Evolutionary History with Meat: 200 to 2.6 Million Years Ago
Mammals evolved from ancestral "mammal-like reptiles" (therapsids, then cynodonts) approximately 220 million years ago (Richard Klein. The Human Career. 2009). Roughly 100 million years ago, placental mammals emerged. The earliest placental mammals are thought to have been nocturnal shrew-like beasts that subsisted primarily on insects, similar to modern shrews and moles. Mammalian teeth continued to show features specialized for insect consumption until the rise of the primates.
65 million years ago, coinciding with the evolution of the first fruiting plants, our ancestors took to the trees and became primates. For most of the time between then and now, our ancestors likely ate the prototypical primate diet of fruit, seeds, leaves/stems, and insects (1). Some primates also hunt smaller animals and thus eat the flesh of mammals, birds, reptiles, amphibians, and fish in addition to insects. However, the contribution of non-insect meat to the diet is usually small.
When we consider the health impacts of eating meat, cardiovascular disease is the first thing that comes to mind. Popular diet advocates often hold diametrically opposed views on the role of meat in cardiovascular disease. Even among researchers and public health officials, opinions vary. In this post, I'll do my best to sort through the literature and determine what the weight of the evidence suggests.
Ancel Keys and the Seven Countries Study
Ancel Keys was one of the first researchers to contribute substantially to the study of the link between diet and cardiovascular disease. Sadly, there is a lot of low-quality information circulating about Ancel Keys and his research (1). The truth is that Keys was a pioneering researcher who conducted some of the most impressive nutritional science of his time. The military "K ration" was designed by Keys, much of what we know about the physiology of starvation comes from his detailed studies during World War II, and he was the original Mediterranean Diet researcher. Science marches on, and not all discoveries are buttressed by additional research, but Keys' work was among the best of his day and must be taken seriously.
One of Keys' earliest contributions to the study of diet and cardiovascular disease appeared in an obscure 1953 paper titled "Atherosclerosis: A Problem in Newer Public Health" (2). This paper is worth reading if you get a chance (freely available online if you poke around a bit). He presents a number of different arguments and supporting data, most of which are widely accepted today, but one graph in particular has remained controversial. This graph shows the association between total fat intake and heart disease mortality in six countries. Keys collected the data from publicly available databases on global health and diet:
Read more »
This post was written by Stephan Guyenet for Whole Health Source.
Is Meat Unhealthy? Part II
Thursday, March 26, 2015 2:19 PM
Over time, animals adapt to the foods they regularly consume. This is how archaeologists can, for example, determine that Triceratops was an herbivore and Tyrannosaurus was a carnivore just by looking at the structure of the skeleton. Adaptations to diet extend beyond skeletal structure, into digestion, metabolism, the brain, musculature, and other aspects of physical function. What is our evolutionary history with meat?
Human Evolutionary History with Meat: 200 to 2.6 Million Years Ago
Mammals evolved from ancestral "mammal-like reptiles" (therapsids, then cynodonts) approximately 220 million years ago (Richard Klein. The Human Career. 2009). Roughly 100 million years ago, placental mammals emerged. The earliest placental mammals are thought to have been nocturnal shrew-like beasts that subsisted primarily on insects, similar to modern shrews and moles. Mammalian teeth continued to show features specialized for insect consumption until the rise of the primates.
65 million years ago, coinciding with the evolution of the first fruiting plants, our ancestors took to the trees and became primates. For most of the time between then and now, our ancestors likely ate the prototypical primate diet of fruit, seeds, leaves/stems, and insects (1). Some primates also hunt smaller animals and thus eat the flesh of mammals, birds, reptiles, amphibians, and fish in addition to insects. However, the contribution of non-insect meat to the diet is usually small.
Semoga artikel Is Meat Unhealthy? bermanfaat bagi Anda.
Post a Comment